A seal is used in a rotating machine such as a turbine in order to prevent gas from leaking along a circumference of a rotor from a high-pressure side to a low-pressure side. The seal is expected to perform a sealing ability in accordance with variations of a clearance between a stator and the rotor of the rotating machine or in accordance with an axial runout between the stator and the rotor. From this aspect, a brush seal made of a bunch of ultrathin wires has been adopted instead of a labyrinth seal.
As shown in FIG. 7, a conventional brush seal 100 mainly includes: a brush body 104 which is formed by a brush 104a made of a bunch of ultrathin wires and an attachment portion 104b to which the brush 104a is welded; a low-pressure-side plate 102; and a high-pressure-side plate 103. This brush seal is configured so that the attachment portion 104b is interposed between the low-pressure-side plate 102 and the high-pressure-side plate 103 and so that outer circumferential portions of the both plates 102, 103 are coupled by a welding 105 to be integrated with each other (see, for example, Patent Citation 1). Further, as shown in FIG. 8, there is an example as a method of fixation for fixing the both plates 102, 103 by making the low-pressure-side plate 102 engaged with the high-pressure-side plate 103 by using a bolt 106 inserted axially in a state where the both plates 102, 103 are overlapped with each other (see, for example, Patent Citation 2).